The Geography of Italy as a whole helped Rome in its conquest because its situation was at the heart of the Mediterranean Sea which was the centre of most civilizations at that time.
Rome was not picked on purpose but had been founded some 700 years before Rome's glory in the Ist century B.C,by the Etruscans who had lived and prospered there (and other places in that part of Italy) for a long time.
Rome at the height of its power and expansion was sitting neatly in the middle of its conquered territories in Asia,North Africa and Europe.
Hope this will answer your question.
